It depends on ones individual circumstances. For most, no biggie. For ray keepers it can be disastrous. Once snails enter a system I break it down. With rays in the tank they will eat the snails. That forces them to propagate in the filters where the excess food builds up. Especially if you feed heavy, moreso if you feed heavy with pellets.
The dead snails can damage pump impellers are worst case cause the impeller to get stuck. That burns up a pump pretty quickly.